Fire suppression systems are commonly used in connection with off-road vehicles, marine vessels, gas stations and commercial buildings, such as for example restaurants, and in like applications where a fire is likely to rapidly expand if not quickly suppressed. Commonly, conventional fire suppression systems suitable for use in such applications operate by dispensing a fire suppression agent in a flow of pressurized gas through a network of distribution pipes or hoses to a plurality of spray nozzles. The pressurized gas may be a chemically non-reactive gas such nitrogen, carbon dioxide, argon, neon, helium or other chemically non-reactive gas, or mixtures of any two or more of these gases. The fire suppression agent may be a wet chemical fire suppression agent, a dry chemical fire suppression agent or a gaseous fire suppression agent.
In conventional fire suppression systems of this type, the fire suppressant, that is the fire suppression agent and gas mixture, is stored under pressure in one or more pressure vessels. Typically, the fire suppressant is stored at a pressure of at least 200 pounds per square inch and in some systems at pressures in excess of 1000 pounds per square inch. A valve is provided in communication with the outlet from the pressure vessel for dispensing the fire suppressant from the gas reservoir within the pressure vessel into the distribution network. This valve must prevent leakage of the high pressure gas from the pressure vessel for long periods of time, but rapidly respond to dispense the high pressure fire suppressant to the distribution network in the event the valve is activated in response to a fire detection signal.
One type of valve often used in conventional fire suppression systems of the type described above is commonly referred to as a balance pressure valve. Conventional balance pressure valves include an axially translatable piston disposed within an axially extending central cavity within the valve body. One end face of the piston is exposed to the gas pressure within the pressure vessel; while the opposite end face of the piston is exposed to the gas pressure within an upper chamber of the valve. A spring biased check valve, operatively associated with an actuator cap disposed at distal end of the central cavity, prevents leakage of the gas from the upper chamber when the check valve is sealed against the actuator cap. In a first position, the piston is located within the central cavity so as to block off the opening to a discharge passage extending radially through the valve body.
When the valve is activated in response to a fire detection signal, the piston is translated axially to a second position whereat the piston is repositioned into the upper chamber of the valve body and the piston no longer blocks the opening to the radially directed discharge passage. In this second position, the high pressure fire suppressant rapidly flows from the reservoir of the pressure vessel into a central cavity of the valve body and out through the discharge passage into the distribution network. The valve is activated by forcibly translating the aforementioned check valve away from the end face of the actuator cap thereby opening a flow passage through which the gas pressure within the upper chamber rapidly vents to atmospheric pressure through a vent port opening to the environment external of the valve, thereby creating a pressure imbalance across the piston, resulting in the piston rapidly translating into the upper chamber under the pressure of the fire suppressant discharging from the pressure vessel.
When used in applications where the fire suppression system is exposed to outdoor conditions or in harsh environments, it is possible for the vent port to become covered over or clogged with ice, particulate, ash or other debris. The build-up of ice or debris over the vent port could adversely impact the reliability of the system. Therefore, it is necessary to periodically check the condition of the vent port and remove any ice or debris that may be blocking the vent port.